Added new options "trace-cmd clear -B <name> -a" which allow the command
to work per ftrace instance:
-B clear the given buffer (may specify multiple -B)
-a clear all existing buffers, including the top level one
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
v2 changes:
- Changed the implementation to use the latest libtracefs APIs.
Documentation/trace-cmd-clear.1.txt | 13 ++-
tracecmd/Makefile | 1 +
tracecmd/trace-clear.c | 126 ++++++++++++++++++++++++++++
tracecmd/trace-record.c | 24 ------
tracecmd/trace-usage.c | 4 +-
5 files changed, 142 insertions(+), 26 deletions(-)
create mode 100644 tracecmd/trace-clear.c
diff --git a/Documentation/trace-cmd-clear.1.txt b/Documentation/trace-cmd-clear.1.txt
index 67e5851a..a0ae36e9 100644
--- a/Documentation/trace-cmd-clear.1.txt
+++ b/Documentation/trace-cmd-clear.1.txt
@@ -7,12 +7,23 @@ trace-cmd-clear - clear the Ftrace buffer.
SYNOPSIS
--------
-*trace-cmd clear*
+*trace-cmd clear* ['OPTIONS']
DESCRIPTION
-----------
The *trace-cmd(1) clear* clears the content of the Ftrace ring buffer.
+OPTIONS
+-------
+*-B* 'buffer-name'::
+ If the kernel supports multiple buffers, this will clear only the given
+ buffer. It does not affect any other buffers. This may be used multiple
+ times to specify different buffers. The top level buffer will not be
+ clearded if this option is given.
+
+*-a*::
+ Clear all existing buffers, including the top level one.
+
SEE ALSO
--------
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1),
diff --git a/tracecmd/Makefile b/tracecmd/Makefile
index 5e59adf8..01f36c61 100644
--- a/tracecmd/Makefile
+++ b/tracecmd/Makefile
@@ -31,6 +31,7 @@ TRACE_CMD_OBJS += trace-show.o
TRACE_CMD_OBJS += trace-list.o
TRACE_CMD_OBJS += trace-usage.o
TRACE_CMD_OBJS += trace-dump.o
+TRACE_CMD_OBJS += trace-clear.o
ifeq ($(VSOCK_DEFINED), 1)
TRACE_CMD_OBJS += trace-tsync.o
endif
diff --git a/tracecmd/trace-clear.c b/tracecmd/trace-clear.c
new file mode 100644
index 00000000..608b9598
--- /dev/null
+++ b/tracecmd/trace-clear.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2008, 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@xxxxxxxxxx>
+ *
+ * Updates:
+ * Copyright (C) 2020, VMware, Tzvetomir Stoyanov <tz.stoyanov@xxxxxxxxx>
+ *
+ */
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+
+#include "tracefs.h"
+#include "trace-local.h"
+
+struct instances_list {
+ struct instances_list *next;
+ struct tracefs_instance *instance;
+};
+
+static int add_new_instance(struct instances_list **list, char *name)
+{
+ struct instances_list *new;
+
+ if (!tracefs_instance_exists(name))
+ return -1;
+ new = calloc(1, sizeof(*new));
+ if (!new)
+ return -1;
+ new->instance = tracefs_instance_create(name);
+ if (!new->instance) {
+ free(new);
+ return -1;
+ }
+
+ new->next = *list;
+ *list = new;
+ return 0;
+}
+
+static int add_instance_walk(const char *name, void *data)
+{
+ return add_new_instance((struct instances_list **)data, (char *)name);
+}
+
+static void clear_list(struct instances_list *list)
+{
+ struct instances_list *del;
+
+ while (list) {
+ del = list;
+ list = list->next;
+ tracefs_instance_free(del->instance);
+ free(del);
+ }
+}
+
+static void clear_instance_trace(struct tracefs_instance *instance)
+{
+ FILE *fp;
+ char *path;
+
+ /* reset the trace */
+ path = tracefs_instance_get_file(instance, "trace");
+ fp = fopen(path, "w");
+ if (!fp)
+ die("writing to '%s'", path);
+ tracefs_put_tracing_file(path);
+ fwrite("0", 1, 1, fp);
+ fclose(fp);
+}
+
+static void clear_trace(struct instances_list *instances)
+{
+ if (instances) {
+ while (instances) {
+ clear_instance_trace(instances->instance);
+ instances = instances->next;
+ }
+ } else
+ clear_instance_trace(NULL);
+}
+
+void trace_clear(int argc, char **argv)
+{
+ struct instances_list *instances = NULL;
+ bool all = false;
+ int c;
+
+ for (;;) {
+ int option_index = 0;
+ static struct option long_options[] = {
+ {"all", no_argument, NULL, 'a'},
+ {"help", no_argument, NULL, '?'},
+ {NULL, 0, NULL, 0}
+ };
+
+ c = getopt_long (argc-1, argv+1, "+haB:",
+ long_options, &option_index);
+ if (c == -1)
+ break;
+ switch (c) {
+ case 'B':
+ if (add_new_instance(&instances, optarg))
+ die("Failed to allocate instance %s", optarg);
+ break;
+ case 'a':
+ all = true;
+ if (tracefs_instances_walk(add_instance_walk, &instances))
+ die("Failed to add all instances");
+ break;
+ case 'h':
+ case '?':
+ default:
+ usage(argv);
+ break;
+ }
+ }
+
+ clear_trace(instances);
+ if (all)
+ clear_trace(NULL);
+ clear_list(instances);
+ exit(0);
+}
+
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 908adb93..3a63f1bd 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -845,21 +845,6 @@ static void clear_trace_instances(void)
__clear_trace(instance);
}
-static void clear_trace(void)
-{
- FILE *fp;
- char *path;
-
- /* reset the trace */
- path = tracefs_get_tracing_file("trace");
- fp = fopen(path, "w");
- if (!fp)
- die("writing to '%s'", path);
- tracefs_put_tracing_file(path);
- fwrite("0", 1, 1, fp);
- fclose(fp);
-}
-
static void reset_max_latency(struct buffer_instance *instance)
{
tracefs_instance_file_write(instance->tracefs,
@@ -6701,15 +6686,6 @@ void trace_profile(int argc, char **argv)
exit(0);
}
-void trace_clear(int argc, char **argv)
-{
- if (argc > 2)
- usage(argv);
- else
- clear_trace();
- exit(0);
-}
-
void trace_record(int argc, char **argv)
{
struct common_record_context ctx;
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index 3f0b2d07..79610bd3 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -180,7 +180,9 @@ static struct usage_help usage_help[] = {
{
"clear",
"clear the trace buffers",
- " %s clear\n"
+ " %s clear [-B buf][-a]\n"
+ " -B clear the given buffer (may specify multiple -B)\n"
+ " -a clear all existing buffers, including the top level one\n"
},
{
"report",
--
2.28.0
|